Odor control has been a significant problem for which there are very few solutions. Ammonia and amines are by far the most objectionable odor. Their volatility makes them quite noticeable when even small amounts are released.
Odor control is of particular interest in the area of human and animal waste disposal. Generally, disposal of waste product from small animals and pets is accomplished by the use of animal litter capable of absorbing waste products. However, conventional litter materials fail to adequately suppress odors.
Odor control is also of interest for products such as foods, clothing, personal care products, foul-smell lagoons, holding tanks and industrial wastes.
Zeolites and imides have been used for odor control. For example, U.S. Pat. No. 5,013,335 discloses the use of zeolites for control of ammonia odor.
U.S. Pat. Nos. 3,776,118 and 3,898,324 teaches inhibiting the formation of odors from poultry farms. These patents disclose the use of a dried fine powder of zeolite with a course powder of crystalline ferrous sulfate hepta-hydrate as a stabilizer. The deodorizing agent disclosed in these patents is the sulfate hepta-hydrate.
In U.S. Pat. No. 4,256,728, zeolites are disclosed for use in a deodorization method. In this patent, however, the zeolite acts as a support for an acid, such acid serving as the deodorization agent.
U.S. Pat. No. 4,059,545 discloses the use of clinoptilolite in the ammonia exchanged form and treated with a dilute solution of a strong acid to act as an absorbent for acid gases.
U.S. Pat. No. 4,437,429 discloses the reduction of ammonia odor from animal litter containing clay by the addition an effective amount of hydrated zeolite. No appreciable odor from wastes was obtained when 10-60% of the total clay/zeolite litter was zeolite.
In U.S. Pat. Nos. 5,833,972 and 5,869,027 the use of an imide for controlling an odor is disclosed.